package com.horstmann.violet.framework.util;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.URLEncoder;
import java.util.Date;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Locale;
import java.util.Properties;
import java.util.StringTokenizer;
import java.util.TimeZone;

/**
 * A simple, tiny, nicely embeddable HTTP 1.0 server in Java
 * 
 * <p>
 * NanoHTTPD version 1.1, Copyright &copy; 2001,2005-2007 Jarno Elonen (elonen@iki.fi, http://iki.fi/elonen/)
 * 
 * <p>
 * <b>Features + limitations: </b>
 * <ul>
 * 
 * <li> Only one Java file </li>
 * <li> Java 1.1 compatible </li>
 * <li> Released as open source, Modified BSD licence </li>
 * <li> No fixed config files, logging, authorization etc. (Implement yourself if you need them.) </li>
 * <li> Supports parameter parsing of GET and POST methods </li>
 * <li> Supports both dynamic content and file serving </li>
 * <li> Never caches anything </li>
 * <li> Doesn't limit bandwidth, request time or simultaneous connections </li>
 * <li> Default code serves files and shows all HTTP parameters and headers</li>
 * <li> File server supports directory listing, index.html and index.htm </li>
 * <li> File server does the 301 redirection trick for directories without '/'</li>
 * <li> File server supports simple skipping for files (continue download) </li>
 * <li> File server uses current directory as a web root </li>
 * <li> File server serves also very long files without memory overhead </li>
 * <li> Contains a built-in list of most common mime types </li>
 * <li> All header names are converted lowercase so they don't vary between browsers/clients </li>
 * 
 * </ul>
 * 
 * <p>
 * <b>Ways to use: </b>
 * <ul>
 * 
 * <li> Run as a standalone app, serves files from current directory and shows requests</li>
 * <li> Subclass serve() and embed to your own program </li>
 * <li> Call serveFile() from serve() with your own base directory </li>
 * 
 * </ul>
 * 
 * See the end of the source file for distribution license (Modified BSD licence)
 */
public class NanoHTTPD
{
    // ==================================================
    // API parts
    // ==================================================

    /**
     * Override this to customize the server.
     * <p>
     * 
     * (By default, this delegates to serveFile() and allows directory listing.)
     * 
     * @parm uri Percent-decoded URI without parameters, for example "/index.cgi"
     * @parm method "GET", "POST" etc.
     * @parm parms Parsed, percent decoded parameters from URI and, in case of POST, data.
     * @parm header Header entries, percent decoded
     * @return HTTP response, see class Response for details
     */
    public Response serve(String uri, String method, Properties header, Properties parms)
    {
        // System.out.println(method + " '" + uri + "' ");

        // Enumeration e = header.propertyNames();
        // while (e.hasMoreElements())
        // {
        // String value = (String) e.nextElement();
        // System.out.println(" HDR: '" + value + "' = '" + header.getProperty(value) + "'");
        // }
        // e = parms.propertyNames();
        // while (e.hasMoreElements())
        // {
        // String value = (String) e.nextElement();
        // System.out.println(" PRM: '" + value + "' = '" + parms.getProperty(value) + "'");
        // }

        return serveFile(uri, header, new File("."), true);
    }

    /**
     * HTTP response. Return one of these from serve().
     */
    public class Response
    {
        /**
         * Default constructor: response = HTTP_OK, data = mime = 'null'
         */
        public Response()
        {
            this.status = HTTP_OK;
        }

        /**
         * Basic constructor.
         */
        public Response(String status, String mimeType, InputStream data)
        {
            this.status = status;
            this.mimeType = mimeType;
            this.data = data;
        }

        /**
         * Convenience method that makes an InputStream out of given text.
         */
        public Response(String status, String mimeType, String txt)
        {
            this.status = status;
            this.mimeType = mimeType;
            this.data = new ByteArrayInputStream(txt.getBytes());
        }

        /**
         * Adds given line to the header.
         */
        public void addHeader(String name, String value)
        {
            header.put(name, value);
        }

        /**
         * HTTP status code after processing, e.g. "200 OK", HTTP_OK
         */
        public String status;

        /**
         * MIME type of content, e.g. "text/html"
         */
        public String mimeType;

        /**
         * Data of the response, may be null.
         */
        public InputStream data;

        /**
         * Headers for the HTTP response. Use addHeader() to add lines.
         */
        public Properties header = new Properties();
    }

    /**
     * Some HTTP response status codes
     */
    public static final String HTTP_OK = "200 OK", HTTP_REDIRECT = "301 Moved Permanently", HTTP_FORBIDDEN = "403 Forbidden",
            HTTP_NOTFOUND = "404 Not Found", HTTP_BADREQUEST = "400 Bad Request", HTTP_INTERNALERROR = "500 Internal Server Error",
            HTTP_NOTIMPLEMENTED = "501 Not Implemented";

    /**
     * Common mime types for dynamic content
     */
    public static final String MIME_PLAINTEXT = "text/plain", MIME_HTML = "text/html",
            MIME_DEFAULT_BINARY = "application/octet-stream";

    // ==================================================
    // Socket & server code
    // ==================================================

    /**
     * Starts a HTTP server to given port.
     * <p>
     * Throws an IOException if the socket is already in use
     */
    public NanoHTTPD(int port) throws IOException
    {
        myTcpPort = port;

        final ServerSocket ss = new ServerSocket(myTcpPort);
        Thread t = new Thread(new Runnable()
        {
            public void run()
            {
                try
                {
                    while (true)
                        new HTTPSession(ss.accept());
                }
                catch (IOException ioe)
                {
                }
            }
        });
        t.setDaemon(true);
        t.start();
    }

    /**
     * Starts as a standalone file server and waits for Enter.
     */
    public static void main(String[] args)
    {
        System.out.println("NanoHTTPD 1.1 (C) 2001,2005-2007 Jarno Elonen\n" + "(Command line options: [port] [--licence])\n");

        // Show licence if requested
        int lopt = -1;
        for (int i = 0; i < args.length; ++i)
            if (args[i].toLowerCase().endsWith("licence"))
            {
                lopt = i;
                System.out.println(LICENCE + "\n");
            }

        // Change port if requested
        int port = 80;
        if (args.length > 0 && lopt != 0) port = Integer.parseInt(args[0]);

        if (args.length > 1 && args[1].toLowerCase().endsWith("licence")) System.out.println(LICENCE + "\n");

        NanoHTTPD nh = null;
        try
        {
            nh = new NanoHTTPD(port);
        }
        catch (IOException ioe)
        {
            System.err.println("Couldn't start server:\n" + ioe);
            System.exit(-1);
        }
        nh.myFileDir = new File("");

        System.out.println("Now serving files in port " + port + " from \"" + new File("").getAbsolutePath() + "\"");
        System.out.println("Hit Enter to stop.\n");

        try
        {
            System.in.read();
        }
        catch (Throwable t)
        {
        }
        ;
    }

    /**
     * Handles one session, i.e. parses the HTTP request and returns the response.
     */
    private class HTTPSession implements Runnable
    {
        public HTTPSession(Socket s)
        {
            mySocket = s;
            Thread t = new Thread(this);
            t.setDaemon(true);
            t.start();
        }

        public void run()
        {
            try
            {
                InputStream is = mySocket.getInputStream();
                if (is == null) return;
                BufferedReader in = new BufferedReader(new InputStreamReader(is));

                // Read the request line
                StringTokenizer st = new StringTokenizer(in.readLine());
                if (!st.hasMoreTokens()) sendError(HTTP_BADREQUEST, "BAD REQUEST: Syntax error. Usage: GET /example/file.html");

                String method = st.nextToken();

                if (!st.hasMoreTokens()) sendError(HTTP_BADREQUEST, "BAD REQUEST: Missing URI. Usage: GET /example/file.html");

                String uri = decodePercent(st.nextToken());

                // Decode parameters from the URI
                Properties parms = new Properties();
                int qmi = uri.indexOf('?');
                if (qmi >= 0)
                {
                    decodeParms(uri.substring(qmi + 1), parms);
                    uri = decodePercent(uri.substring(0, qmi));
                }

                // If there's another token, it's protocol version,
                // followed by HTTP headers. Ignore version but parse headers.
                // NOTE: this now forces header names uppercase since they are
                // case insensitive and vary by client.
                Properties header = new Properties();
                if (st.hasMoreTokens())
                {
                    String line = in.readLine();
                    while (line.trim().length() > 0)
                    {
                        int p = line.indexOf(':');
                        header.put(line.substring(0, p).trim().toLowerCase(), line.substring(p + 1).trim());
                        line = in.readLine();
                    }
                }

                // If the method is POST, there may be parameters
                // in data section, too, read it:
                if (method.equalsIgnoreCase("POST"))
                {
                    long size = 0x7FFFFFFFFFFFFFFFl;
                    String contentLength = header.getProperty("content-length");
                    if (contentLength != null)
                    {
                        try
                        {
                            size = Integer.parseInt(contentLength);
                        }
                        catch (NumberFormatException ex)
                        {
                        }
                    }
                    String postLine = "";
                    char buf[] = new char[512];
                    int read = in.read(buf);
                    while (read >= 0 && size > 0 && !postLine.endsWith("\r\n"))
                    {
                        size -= read;
                        postLine += String.valueOf(buf, 0, read);
                        if (size > 0) read = in.read(buf);
                    }
                    postLine = postLine.trim();
                    decodeParms(postLine, parms);
                }

                // Ok, now do the serve()
                Response r = serve(uri, method, header, parms);
                if (r == null) sendError(HTTP_INTERNALERROR, "SERVER INTERNAL ERROR: Serve() returned a null response.");
                else sendResponse(r.status, r.mimeType, r.header, r.data);

                in.close();
            }
            catch (IOException ioe)
            {
                try
                {
                    sendError(HTTP_INTERNALERROR, "SERVER INTERNAL ERROR: IOException: " + ioe.getMessage());
                }
                catch (Throwable t)
                {
                }
            }
            catch (InterruptedException ie)
            {
                // Thrown by sendError, ignore and exit the thread.
            }
        }

        /**
         * Decodes the percent encoding scheme. <br/> For example: "an+example%20string" -> "an example string"
         */
        private String decodePercent(String str) throws InterruptedException
        {
            try
            {
                StringBuffer sb = new StringBuffer();
                for (int i = 0; i < str.length(); i++)
                {
                    char c = str.charAt(i);
                    switch (c)
                    {
                    case '+':
                        sb.append(' ');
                        break;
                    case '%':
                        sb.append((char) Integer.parseInt(str.substring(i + 1, i + 3), 16));
                        i += 2;
                        break;
                    default:
                        sb.append(c);
                        break;
                    }
                }
                return new String(sb.toString().getBytes());
            }
            catch (Exception e)
            {
                sendError(HTTP_BADREQUEST, "BAD REQUEST: Bad percent-encoding.");
                return null;
            }
        }

        /**
         * Decodes parameters in percent-encoded URI-format ( e.g. "name=Jack%20Daniels&pass=Single%20Malt" ) and adds them to given
         * Properties.
         */
        private void decodeParms(String parms, Properties p) throws InterruptedException
        {
            if (parms == null) return;

            StringTokenizer st = new StringTokenizer(parms, "&");
            while (st.hasMoreTokens())
            {
                String e = st.nextToken();
                int sep = e.indexOf('=');
                if (sep >= 0) p.put(decodePercent(e.substring(0, sep)).trim(), decodePercent(e.substring(sep + 1)));
            }
        }

        /**
         * Returns an error message as a HTTP response and throws InterruptedException to stop furhter request processing.
         */
        private void sendError(String status, String msg) throws InterruptedException
        {
            sendResponse(status, MIME_PLAINTEXT, null, new ByteArrayInputStream(msg.getBytes()));
            throw new InterruptedException();
        }

        /**
         * Sends given response to the socket.
         */
        private void sendResponse(String status, String mime, Properties header, InputStream data)
        {
            try
            {
                if (status == null) throw new Error("sendResponse(): Status can't be null.");

                OutputStream out = mySocket.getOutputStream();
                PrintWriter pw = new PrintWriter(out);
                pw.print("HTTP/1.0 " + status + " \r\n");

                if (mime != null) pw.print("Content-Type: " + mime + "\r\n");

                if (header == null || header.getProperty("Date") == null) pw.print("Date: " + gmtFrmt.format(new Date()) + "\r\n");

                if (header != null)
                {
                    Enumeration<Object> e = header.keys();
                    while (e.hasMoreElements())
                    {
                        String key = (String) e.nextElement();
                        String value = header.getProperty(key);
                        pw.print(key + ": " + value + "\r\n");
                    }
                }

                pw.print("\r\n");
                pw.flush();

                if (data != null)
                {
                    byte[] buff = new byte[2048];
                    while (true)
                    {
                        int read = data.read(buff, 0, 2048);
                        if (read <= 0) break;
                        out.write(buff, 0, read);
                    }
                }
                out.flush();
                out.close();
                if (data != null) data.close();
            }
            catch (IOException ioe)
            {
                // Couldn't write? No can do.
                try
                {
                    mySocket.close();
                }
                catch (Throwable t)
                {
                }
            }
        }

        private Socket mySocket;
    };

    /**
     * URL-encodes everything between "/"-characters. Encodes spaces as '%20' instead of '+'.
     */
    private String encodeUri(String uri)
    {
        String newUri = "";
        StringTokenizer st = new StringTokenizer(uri, "/ ", true);
        while (st.hasMoreTokens())
        {
            String tok = st.nextToken();
            if (tok.equals("/")) newUri += "/";
            else if (tok.equals(" ")) newUri += "%20";
            else
            {
                // Deprecated Java 1.1 compliant code -> newUri += URLEncoder.encode( tok );
                // For Java 1.4 you'll want to use this instead:
                try
                {
                    newUri += URLEncoder.encode(tok, "UTF-8");
                }
                catch (UnsupportedEncodingException uee)
                {
                    // Well, we tried...
                }
            }
        }
        return newUri;
    }

    private int myTcpPort;
    File myFileDir;

    // ==================================================
    // File server code
    // ==================================================

    /**
     * Serves file from homeDir and its' subdirectories (only). Uses only URI, ignores all headers and HTTP parameters.
     */
    public Response serveFile(String uri, Properties header, File homeDir, boolean allowDirectoryListing)
    {
        // Make sure we won't die of an exception later
        if (!homeDir.isDirectory()) return new Response(HTTP_INTERNALERROR, MIME_PLAINTEXT,
                "INTERNAL ERRROR: serveFile(): given homeDir is not a directory.");

        // Remove URL arguments
        uri = uri.trim().replace(File.separatorChar, '/');
        if (uri.indexOf('?') >= 0) uri = uri.substring(0, uri.indexOf('?'));

        // Prohibit getting out of current directory
        if (uri.startsWith("..") || uri.endsWith("..") || uri.indexOf("../") >= 0) return new Response(HTTP_FORBIDDEN,
                MIME_PLAINTEXT, "FORBIDDEN: Won't serve ../ for security reasons.");

        File f = new File(homeDir, uri);
        if (!f.exists()) return new Response(HTTP_NOTFOUND, MIME_PLAINTEXT, "Error 404, file not found.");

        // List the directory, if necessary
        if (f.isDirectory())
        {
            // Browsers get confused without '/' after the
            // directory, send a redirect.
            if (!uri.endsWith("/"))
            {
                uri += "/";
                Response r = new Response(HTTP_REDIRECT, MIME_HTML, "<html><body>Redirected: <a href=\"" + uri + "\">" + uri
                        + "</a></body></html>");
                r.addHeader("Location", uri);
                return r;
            }

            // First try index.html and index.htm
            if (new File(f, "index.html").exists()) f = new File(homeDir, uri + "/index.html");
            else if (new File(f, "index.htm").exists()) f = new File(homeDir, uri + "/index.htm");

            // No index file, list the directory
            else if (allowDirectoryListing)
            {
                String[] files = f.list();
                String msg = "<html><body><h1>Directory " + uri + "</h1><br/>";

                if (uri.length() > 1)
                {
                    String u = uri.substring(0, uri.length() - 1);
                    int slash = u.lastIndexOf('/');
                    if (slash >= 0 && slash < u.length()) msg += "<b><a href=\"" + uri.substring(0, slash + 1)
                            + "\">..</a></b><br/>";
                }

                for (int i = 0; i < files.length; ++i)
                {
                    File curFile = new File(f, files[i]);
                    boolean dir = curFile.isDirectory();
                    if (dir)
                    {
                        msg += "<b>";
                        files[i] += "/";
                    }

                    msg += "<a href=\"" + encodeUri(uri + files[i]) + "\">" + files[i] + "</a>";

                    // Show file size
                    if (curFile.isFile())
                    {
                        long len = curFile.length();
                        msg += " &nbsp;<font size=2>(";
                        if (len < 1024) msg += curFile.length() + " bytes";
                        else if (len < 1024 * 1024) msg += curFile.length() / 1024 + "." + (curFile.length() % 1024 / 10 % 100)
                                + " KB";
                        else msg += curFile.length() / (1024 * 1024) + "." + curFile.length() % (1024 * 1024) / 10 % 100 + " MB";

                        msg += ")</font>";
                    }
                    msg += "<br/>";
                    if (dir) msg += "</b>";
                }
                return new Response(HTTP_OK, MIME_HTML, msg);
            }
            else
            {
                return new Response(HTTP_FORBIDDEN, MIME_PLAINTEXT, "FORBIDDEN: No directory listing.");
            }
        }

        try
        {
            // Get MIME type from file name extension, if possible
            String mime = null;
            int dot = f.getCanonicalPath().lastIndexOf('.');
            if (dot >= 0) mime = (String) theMimeTypes.get(f.getCanonicalPath().substring(dot + 1).toLowerCase());
            if (mime == null) mime = MIME_DEFAULT_BINARY;

            // Support (simple) skipping:
            long startFrom = 0;
            String range = header.getProperty("Range");
            if (range != null)
            {
                if (range.startsWith("bytes="))
                {
                    range = range.substring("bytes=".length());
                    int minus = range.indexOf('-');
                    if (minus > 0) range = range.substring(0, minus);
                    try
                    {
                        startFrom = Long.parseLong(range);
                    }
                    catch (NumberFormatException nfe)
                    {
                    }
                }
            }

            FileInputStream fis = new FileInputStream(f);
            fis.skip(startFrom);
            Response r = new Response(HTTP_OK, mime, fis);
            r.addHeader("Content-length", "" + (f.length() - startFrom));
            r.addHeader("Content-range", "" + startFrom + "-" + (f.length() - 1) + "/" + f.length());
            return r;
        }
        catch (IOException ioe)
        {
            return new Response(HTTP_FORBIDDEN, MIME_PLAINTEXT, "FORBIDDEN: Reading file failed.");
        }
    }

    /**
     * Hashtable mapping (String)FILENAME_EXTENSION -> (String)MIME_TYPE
     */
    private static Hashtable<String, String> theMimeTypes = new Hashtable<String, String>();
    static
    {
        StringTokenizer st = new StringTokenizer("htm        text/html " + "html       text/html " + "txt        text/plain "
                + "asc        text/plain " + "gif        image/gif " + "jpg        image/jpeg " + "jpeg       image/jpeg "
                + "png        image/png " + "mp3        audio/mpeg " + "m3u        audio/mpeg-url " + "pdf        application/pdf "
                + "doc        application/msword " + "ogg        application/x-ogg " + "zip        application/octet-stream "
                + "exe        application/octet-stream " + "class      application/octet-stream ");
        while (st.hasMoreTokens())
            theMimeTypes.put(st.nextToken(), st.nextToken());
    }

    /**
     * GMT date formatter
     */
    private static java.text.SimpleDateFormat gmtFrmt;
    static
    {
        gmtFrmt = new java.text.SimpleDateFormat("E, d MMM yyyy HH:mm:ss 'GMT'", Locale.US);
        gmtFrmt.setTimeZone(TimeZone.getTimeZone("GMT"));
    }

    /**
     * The distribution licence
     */
    private static final String LICENCE = "Copyright (C) 2001,2005 by Jarno Elonen <elonen@iki.fi>\n" + "\n"
            + "Redistribution and use in source and binary forms, with or without\n"
            + "modification, are permitted provided that the following conditions\n" + "are met:\n" + "\n"
            + "Redistributions of source code must retain the above copyright notice,\n"
            + "this list of conditions and the following disclaimer. Redistributions in\n"
            + "binary form must reproduce the above copyright notice, this list of\n"
            + "conditions and the following disclaimer in the documentation and/or other\n"
            + "materials provided with the distribution. The name of the author may not\n"
            + "be used to endorse or promote products derived from this software without\n"
            + "specific prior written permission. \n" + " \n"
            + "THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR\n"
            + "IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES\n"
            + "OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.\n"
            + "IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,\n"
            + "INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT\n"
            + "NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,\n"
            + "DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY\n"
            + "THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT\n"
            + "(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE\n"
            + "OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.";
}
